A two-region model of the solar wind with collisionless electron heat flux

ALEXANDER, P.

ASTROPHYSICAL JOURNAL

IOP PUBLISHING LTD

Año: 1993 vol. 414

0004-637X

The present model divides the interplanetary space into an "inner region" and an "outer region." The solar wind is assumed to be one-fluid in the former zone and two-fluid in the latter  zone, where a new equation  for the electron  heat flux replaces the classical heat conduction  law because the plasma is not collision dominated. The model produces solutions  for all physical quantities  as functions of heliocentric distance  that  are in good agreement  with  quiet-time  observations.  The  numerical  results and  a new interpretation of the  gravitational potential  energy show that  the main energy conversions in the solar coronal expansion  are from heat conduc­ tion  and  enthalpy  into  mechanical energy, whereas  the magnetic  component  plays an  insignificant  role. It is also found  that  the total energy equation  cannot  be replaced by the polytropic law.